Salt Mixing do’s and don’ts?

[FishFilet]

I’ve been given advice from a gentleman regarding mixing salt with high temperature water for faster dissolution. He also told me that slowly adding the salt would prevent precipitation.

I’ve been reef keeping for decades. Way back when we were told to add an aerator to the mixing pump. Now it’s said that actually causes precipitation.

So is the advice I’ve been given sound?

 

[bushdoc]

Reputable salt manufactures give you exact instructions how to mix their products. Generally you are suppose to add salt slowly to RODI water while mixing it. Usually temp suppose to be about 75-77F. Never heard about aerating it. Also how long you suppose to mix it depends on manufacturer and I have seen anything from 15 min to 2h.

 

[Danny McElroy]

Thats interesting, I've been reef keeping since 2014, and have always followed the instructions on the salt from the manufacturer.... that seems like the safe bet.

 

[Randy Holmes-Farley]

It's a complicated question.

IMO, the best method is to fill the container with water, get it stirring, slowly add the salt, then (and only then) heat it.

Reasons:

1. Calcium carbonate (the main precipitation problem from poor mixing) is more soluble at lower temps (unlike many chemicals).

2. A pile of salt at the bottom locally pushes alk and calcium very high, risking precipitation.

Is faster dissolution at higher temps desirable? I doubt it, but cannot prove it wrong without seeing an experiment. There's less time in a pile at the bottom, but less solubility of calcium carbonate.

Red Sea specifically recommends against heating (even from stirring for too long) for their very precipitation-prone Red Sea Coral Pro (due to the high alk).

Would an aerator increase precipitation? Depends on the mix and the CO2 level in your air. If the aeration is blowing off CO2 and raising pH, it will increase precipitation potential. if the mix is sucking in CO2 and lowering the pH then it will reduce the precipitation potential.

Note that salt mixes are much more prone to precipitation than a reef tank at the same alk/cal/mag parameters due to missing organics and phosphate which tend to get onto growing calcium carbonate surfaces and stop precipitation.

 

[CoralB]

Throw a circulating pump in and forget about it . Even the air stone idea is not something I wouldn’t do because of salt creep . Crazy !! Don’t over think it ,if you use a somewhat clean salt a pump should make it ready 12 hrs or less . I mix mine in 76 degrees room temp and it’s all good . Somethings don’t need to be improved . If you want to mix it in warmer temps then do it in the garage . Maybe warmer temps mix faster I don’t know . 6-12 hrs should be fine unless you need it for an emergency you could always buy it from you lfs .

 

[Randy Holmes-Farley]

Thats interesting, I've been reef keeping since 2014, and have always followed the instructions on the salt from the manufacturer.... that seems like the safe bet.

Maybe, maybe not. They cannot now your home CO2 levels, and may not even understand the process. Don't give manufacturers more chemical knowledge credit than they deserve since many make other very serious errors in understanding their own products.

FWIW, a Red Sea tech rep spouted nonsense when I tried to ask about their conflicting instructions to stir but not aerate, which is technically very difficult.

 

[CoralB]

And or what Randy said lol !!

 

[CoralB]

Maybe, maybe not. They cannot now your home CO2 levels, and may not even understand the process. Don't give manufacturers more chemical knowledge credit than they deserve since many make other very serious errors in understanding their own products.

FWIW, a Red Sea tech rep spouted nonsense when I tried to ask about their conflicting instructions to stir but not aerate, which is technically very difficult.

Is that why James Bond always says he likes his shaken not stirred

 

[Randy Holmes-Farley]

Is that why James Bond always says he likes his shaken not stirred

I think so, yes. lol